AD 77-25-02
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Sabreliner Corporation | NA-265-70 | Airworthiness Directives; ROCKWELL INTERNATIONAL Model NA-265-70 and NA-265-80 Airplanes |
| aircraft | Sabreliner Corporation | NA-265-80 | Airworthiness Directives; ROCKWELL INTERNATIONAL Model NA-265-70 and NA-265-80 Airplanes |
Unsafe Condition
Deactivation of the engine fire detection system and/or crossed wires in the engine fire detectors to cockpit warning light.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Ensure proper ground between engine fire detector element couplings and engine, verify continuity between elements and fire detector control units per Service Bulletin 30, install new clamps (P/N AN 742-H3), perform continuity checks with a Volt/OHM meter, conduct fire warning system tests using jumper wires and test switches, and ensure proper illumination of fire pull handle lights. Equivalent modifications may be used with FAA approval.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Prior to the next flight after receipt of this telegram, unless already accomplished.
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Sabreliner Corporation Model NA-265-70 (Serial Numbers 370-1 and 370-7) and NA-265-80 (Serial Numbers 380-1 through 380-58).
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
Engine Fire Detection System
Applicability Source Text
Show captured applicability text from the source AD
AD Final Rules - DRS_77-25-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 77-25-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; ROCKWELL INTERNATIONAL Model NA-265-70 and NA-265-80 Airplanes Subject: Engine Fire Detection System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/12/1977 Make: Sabreliner Corporation Model: NA-265-70 | NA-265-80 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 77-25-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3091 AD NUMBER: 77-25-02 SUBJECT HEADING: Airworthiness Directives; ROCKWELL INTERNATIONAL Model NA-265-70 and NA-265-80 Airplanes ACTION: SUMMARY: DATES: Effective December 12, 1977. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 77-25-02 ROCKWELL INTERNATIONAL: Amendment 39-3091. Applies to Sabreliner Model NA-265-70 Serial Numbers 370-1 and 370-7, and NA-265-80 Serial Numbers 380-1 through 380-58, certificated in all categories. Compliance required as indicated. To prevent deactivation of the engine fire detection system and/or crossed wires in the engine fire detectors to cockpit warning light, accomplish the following: Prior to the next flight after receipt of this telegram, unless already accomplished, A. Ensure that a proper ground exists between the engine fire detector element (Edison Cable P/N 244-12482) couplings and the engine, and B. Ensure that proper continuity exists between the elements and the fire detector control units in accordance with Rockwell International Sabreliner Service Bulletin No. 30 dated November 2, 1977, or later FAA approved revisions, or accomplish tests and modifications as follows: 1. Disconnect electrical power from airplane. 2. Open and remove engine access doors as required. 3. Locate and remove existing MS 21105-4 clamps securing fire detector element couplings to engine. (Ref. Aeronca Dwg. No. 234-22029 Rev. A). 4. Install new clamps (P/N AN 742-H3) on each fire detector element coupling. Tighten clamp fasteners. 5. Using a Volt/OHM meter (Simpson 260 or equivalent) set to read OHMS, connect negative (-) lead to AIRFRAME GROUND and positive (+) lead to fire detector element coupling. Check that meter reads one OHM or less. Remove Volt/OHM meter leads. 6. On RH engine, disconnect fire detector element from ONE coupling. Apply external power to airplane. 7. Using a suitable jumper wire, attach one end of jumper wire to inner conductor of receptacle, and the other end of jumper wire to ground. Check that the right hand "Fire Pull" handle lights illuminate. Remove jumper from receptacle inner conductor and insert in center conductor of fire detector element. Check that right hand "Fire Pull" handle lights illuminate. Remove jumper wire. 8. Connect and tighten fire detector element to couplings (element disconnected in Step 6). Lockwire coupling. 9. On LH engine, disconnect fire detector element from ONE coupling. 10. Using a suitable jumper wire, attach one end of jumper wire to inner conductor of receptacle, and the other end of jumper wire to ground. Check that the left hand "Fire Pull" handle lights illuminate. Remove jumper from receptacle inner conductor and insert in center conductor of fire detector element. Check that left hand "Fire Pull" handle lights illuminate. Remove jumper wire. 11. Connect and tighten fire detector element to coupling (element disconnected in Step 9). Lockwire coupling. NOTE: If the requirements of Step 7 thru Step 10 are not met, check fire detector wiring in accordance with Rockwell International Sabreliner Wiring Diagram Manual, Report No. SR-73-26. 12. Press "Fire Det Sys Push To Test" switch. Right and left "Fire Pull" overheat and fire-warning indicator lights should illuminate within one second after switch is pushed. Make sure both lights in each assembly illuminate. Release test switch. Both lights should go out within 5 seconds. Remove electrical power from airplane. 13. Close and/or install engine cowling. C. Equivalent modifications may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. D. Special flight permits may be issued in accordance with FAR's 21.197 and 21.199 to authorize operation of an airplane to a base for the accomplishment of the modifications required by this AD provided the following is accomplished: 1. Interim addition of a positive ground between the engine fire detector element couplings and the engine to ensure proper operation of the engine fire detection system, and 2. Check the fire warning system to ensure that the fire warning light operates correctly for the engine/engines involved. This amendment becomes effective December 12, 1977, for all persons except those to whom it was made effective by telegram dated November 4, 1977 which contained this amendment. FOOTER:
Document Text
Show stored source text (verify against official source)
AD Final Rules - DRS_77-25-02.html Copy URL Print/Save as PDF Document Versions Feedback Details AD Number: 77-25-02 Document Type: AD Final Rules Docket Number: Unknown Subject Heading: Airworthiness Directives; ROCKWELL INTERNATIONAL Model NA-265-70 and NA-265-80 Airplanes Subject: Engine Fire Detection System Status: Current Citation: This information is not available. Citation Publish Date: Effective Date: 12/12/1977 Make: Sabreliner Corporation Model: NA-265-70 | NA-265-80 Product Type: Aircraft Product Subtype: Large Airplane Affected AD: Superseded AD: Affected By: Superseded By: Service/Office: Office of Primary Responsibility: CFR Part Reference: Part 39 Comments: AIRWORTHINESS DIRECTIVES FINAL RULES: 77-25-02 CITATION: This information is not available. PAGE NUMBER: DOCKET NUMBER: Unknown AMENDMENT: 39-3091 AD NUMBER: 77-25-02 SUBJECT HEADING: Airworthiness Directives; ROCKWELL INTERNATIONAL Model NA-265-70 and NA-265-80 Airplanes ACTION: SUMMARY: DATES: Effective December 12, 1977. ADDRESSES: FOR FURTHER INFORMATION CONTACT: SUPPLEMENTARY INFORMATION: REGULATORY TEXT: 77-25-02 ROCKWELL INTERNATIONAL: Amendment 39-3091. Applies to Sabreliner Model NA-265-70 Serial Numbers 370-1 and 370-7, and NA-265-80 Serial Numbers 380-1 through 380-58, certificated in all categories. Compliance required as indicated. To prevent deactivation of the engine fire detection system and/or crossed wires in the engine fire detectors to cockpit warning light, accomplish the following: Prior to the next flight after receipt of this telegram, unless already accomplished, A. Ensure that a proper ground exists between the engine fire detector element (Edison Cable P/N 244-12482) couplings and the engine, and B. Ensure that proper continuity exists between the elements and the fire detector control units in accordance with Rockwell International Sabreliner Service Bulletin No. 30 dated November 2, 1977, or later FAA approved revisions, or accomplish tests and modifications as follows: 1. Disconnect electrical power from airplane. 2. Open and remove engine access doors as required. 3. Locate and remove existing MS 21105-4 clamps securing fire detector element couplings to engine. (Ref. Aeronca Dwg. No. 234-22029 Rev. A). 4. Install new clamps (P/N AN 742-H3) on each fire detector element coupling. Tighten clamp fasteners. 5. Using a Volt/OHM meter (Simpson 260 or equivalent) set to read OHMS, connect negative (-) lead to AIRFRAME GROUND and positive (+) lead to fire detector element coupling. Check that meter reads one OHM or less. Remove Volt/OHM meter leads. 6. On RH engine, disconnect fire detector element from ONE coupling. Apply external power to airplane. 7. Using a suitable jumper wire, attach one end of jumper wire to inner conductor of receptacle, and the other end of jumper wire to ground. Check that the right hand "Fire Pull" handle lights illuminate. Remove jumper from receptacle inner conductor and insert in center conductor of fire detector element. Check that right hand "Fire Pull" handle lights illuminate. Remove jumper wire. 8. Connect and tighten fire detector element to couplings (element disconnected in Step 6). Lockwire coupling. 9. On LH engine, disconnect fire detector element from ONE coupling. 10. Using a suitable jumper wire, attach one end of jumper wire to inner conductor of receptacle, and the other end of jumper wire to ground. Check that the left hand "Fire Pull" handle lights illuminate. Remove jumper from receptacle inner conductor and insert in center conductor of fire detector element. Check that left hand "Fire Pull" handle lights illuminate. Remove jumper wire. 11. Connect and tighten fire detector element to coupling (element disconnected in Step 9). Lockwire coupling. NOTE: If the requirements of Step 7 thru Step 10 are not met, check fire detector wiring in accordance with Rockwell International Sabreliner Wiring Diagram Manual, Report No. SR-73-26. 12. Press "Fire Det Sys Push To Test" switch. Right and left "Fire Pull" overheat and fire-warning indicator lights should illuminate within one second after switch is pushed. Make sure both lights in each assembly illuminate. Release test switch. Both lights should go out within 5 seconds. Remove electrical power from airplane. 13. Close and/or install engine cowling. C. Equivalent modifications may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. D. Special flight permits may be issued in accordance with FAR's 21.197 and 21.199 to authorize operation of an airplane to a base for the accomplishment of the modifications required by this AD provided the following is accomplished: 1. Interim addition of a positive ground between the engine fire detector element couplings and the engine to ensure proper operation of the engine fire detection system, and 2. Check the fire warning system to ensure that the fire warning light operates correctly for the engine/engines involved. This amendment becomes effective December 12, 1977, for all persons except those to whom it was made effective by telegram dated November 4, 1977 which contained this amendment. FOOTER:
Source: Official FAA Source ↗
Retrieved: Apr 8, 2026
Rights: U.S. Government Public Domain
This site is not affiliated with or endorsed by the FAA. Always verify with official sources.